The present invention relates to an insulated, waterproof cover for the connection between an electrical cable and a sacrificial anode for underground use.
Underground metal pipe is subject to corrosion due to the presence of water in the surrounding soil. The water acts as an electrolyte and the pipe develops a slight potential difference between various sections, which causes some areas to behave as anodes and some as cathodes. The metal passes into solution at the anodes to form a metal oxide or hydroxide and release hydrogen as in a battery, the reaction being primarily electrochemical in nature. A traditional means of combating pipe corrosion is to cause the pipe to behave as a cathode by electrically connecting the pipe to a material anodic to the pipe, which causes the anode to preferentially corrode. Materials such as zinc or carbon are often used as sacrificial anodes to protect iron pipe, and a slight current is provided to charge the pipe to a negative voltage. An increase in resistance provides notice that a sacrificial anode is thoroughly corroded and must be replaced in order to protect the pipe.
Carbon anodes are popular for such cathodic protection and are commonly manufactured by providing a bore in the end of a cylindrical carbon rod and inserting the exposed end of an insulated electrical cable into the bore and completing the electrical connection with molten lead between the exposed conductor and the carbon. The connection must then be sealed to prevent the anodic reaction which would result from the intrusion of moisture. One seal presently available is a boot profiled to fit over the end of the carbon rod, the boot having an extended tubular section profiled to fit around the cable. The boot is of heat recoverable material and is designed to fit loosely for ease in application, the boot subsequently being shrunk by application of heat. In such a device, lateral movement of the wire causes it to bend where it enters the bore in the anode, causing stress on the boot at the juncture with the tubular section.